The present invention generally relates to an automatic waterproofing apparatus for a joint of electric wires and more particularly, to an automatic waterproofing apparatus for automatically waterproofing a joint of electric wires in a wiring harness used for wiring in a motor vehicle, a motor cycle, a ship, etc.
Various structures for waterproofing a joint of electric wires have been proposed so far. For example, in one known structure for waterproofing a joint of electric wires, an insulating tape is wound around the joint. Meanwhile, in another known structure, a butyl rubber sheet or a butyl rubber tape is wound around the joint of the electric wires and then, external force is applied to the wound sheet or tape.
Meanwhile, as shown in FIG. 1, Japanese Patent Laid-Open Publication No. 2-257579 (1990) proposes a waterproof structure in which when conductors 3 exposed from insulating coatings 1 of electric wires 2A and 2B, respectively, are connected to each other so as to form a joint 4, the joint 4 is covered by an insulating cover 5 and then, urethane elastomer is filled into the insulating cover 5. Furthermore, a waterproof structure in which after a joint of electric wires has been covered by a container formed by vacuum forming or an insulating sheet, silicone resin or ultraviolet-curing resin is injected into the container or the insulating sheet is known from Japanese Patent Laid-Open Publication No. 4-229961 (1992), Japanese Utility Model Laid-Open Publication No. 64-55670 (1989) or Japanese Patent Laid-Open Publication No. 1-154473 (1989).
However, the above mentioned known waterproof structures have the following drawbacks. Initially, in case the insulating tape is wound around the joint of the electric wires, it is difficult to wind the insulating tape around the joint of the electric wires closely without producing a gap between the insulating tape and the joint, thereby resulting in a possibility of incomplete waterproofing. Meanwhile, in case the butyl rubber sheet or the like is wound around the joint of the electric wires and then, external force is applied to the butyl rubber sheet, the butyl rubber sheet cannot follow a bent portion of the wire properly, so that the butyl rubber sheet is not brought into close contact with the joint, thus resulting in a risk of incomplete waterproofing. Furthermore, in case the joint of the electric wires is disposed in the insulating cover or the like and then, urethane elastomer is filled into the insulating cover, the waterproofed joint becomes large in size and thus, it is improper to bundle a plurality of the waterproofed joints by using an adhesive tape or the like.
In addition, all the above mentioned known waterproofing operations should be performed manually by an operator. Therefore, it is difficult to perform the known waterproofing operations automatically by an apparatus or waterproof a number of the joints of the electric wires continuously by the known waterproofing operations.